Onyxx is a stylized form of Onyx, from Greek, referring to the black gemstone.
Onyxx is a creatively respelled variant of Onyx, the striking banded gemstone whose name descends from the ancient Greek "onyx," meaning "fingernail" or "claw" — a reference to the translucent, flesh-like veining found in some specimens. The Greeks wove myth around the stone: according to Ovid, Cupid accidentally clipped the divine fingernails of Venus while she slept, and the gods transformed the clippings into onyx so that no part of a celestial body would ever truly perish. That origin myth gives the stone — and the name — a quietly immortal quality.
Onyx entered English as a gemstone name in the medieval period and spent centuries as a jeweler's term before the twentieth century's appetite for bold, mineralogical names brought it into the nursery. The gemstone itself, typically deep black with white banding, has long been associated with strength, focus, and protection across multiple cultures — in ancient Rome, warriors carried onyx carvings of Hercules into battle; in Persian tradition, the stone was believed to ward off evil. The double-x spelling of Onyxx is a contemporary stylistic choice that amplifies the name's visual impact, echoing the maximalist naming aesthetic of the 2000s and 2010s.
It transforms a single-letter ending into a graphic flourish, giving the name a harder, more angular edge that suits its association with the darkly beautiful stone. As gemstone names continue to flourish for both boys and girls, Onyxx occupies the boldest, most visually assertive corner of that trend.